The CAS Registry Mumber 53547-96-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,5,4 and 7 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 53547-96: (7*5)+(6*3)+(5*5)+(4*4)+(3*7)+(2*9)+(1*6)=139 139 % 10 = 9 So 53547-96-9 is a valid CAS Registry Number.